Injector

ABSTRACT

A proportioning injector for injecting a fluid in a positive displacement pump cavity. A passage extends through the injector housing between an inlet for supplying the injection fluid and an outlet for discharging the fluid to the cavity. A chamber is located in the passage and a double-headed piston member having piston surfaces exposed to the chamber and to the pump cavity is located in the chamber to vary the volume of the chamber. The fluid is injected into the pump cavity during the intake cycle of the pump and the chamber is filled with fluid to be injected during the discharge cycle of the pump.

United States Patent [72] Inventor Leonard F. Janssen Des Moines, Iowa 21 Appl. No. 758,722 221 Filed Sept. 10, 1968 [45] Patented May 18, 1971 [73] Assignee Delavan Manufacturing Co.

54 INJECTOR 11 Claims, 1 Drawing Fig. [52] US. Cl 417/245, 417/349, 417/503 [51] Int. Cl ..F04b 25/00, F04b 17/00, F04b 23/06 [50] Field of Search 103/44, 6, 9, 7, 2, 45; 417/503, 245 [56] References Cited UNITED STATES PATENTS 1,322,236 11/1919 Fish 103/9 269,666 12/1882 Hays 103/44 1,569,435 1/ 1926 Myers 103/6 Primary Examiner-William L. Freeh Attorney-Molinare, Allegretti, Newitt and Witcoff ABSTRACT: A proportioning injector for injecting a fluid in-a positive displacement pump cavity. A passage extends through the injector housing between an inlet for supplying the injection fluid and an outlet for discharging the fluid to the cavity. A chamber is located in the passage and a double-headed piston member having piston surfaces exposed to the chamber and to the pump cavity is located in the chamber to vary the volume of the chamber. The fluid is injected into the pump cavity during the intake cycle of the pump and the chamber is filled with fluid to be injected during the discharge cycle of the pump.

INJECTOR BACKGROUND OF THE INVENTION This invention relates to an injector for fluids and, more particularly, to a proportioning injector for injecting an injection fluid into the pumping cavity of a positive displacement pump during its intake cycle.

In the past various injectors have been provided for use with positive displacement pumps for the injection of fluids, such as detergent admixtures and the like in such applications as industrial or vehicle washing and other industrial cleaning operations. Such prior injectors have various merits but all are handicapped in one respect or another due to limitations of their basic principles of operation or construction.

One such prior device injects the injection fluid into the high pressure pump discharge stream. Such construction consumes a substantial portion of the energy of the pump and thus substantially decreases the efiiciency of the pumps primary function of pumping the water or other principal fluid. Also such discharge injector generally employs a double-headed piston with each of the heads having a sliding seal and the larger head being exposed to the pump cavity and maximum pressure. Since two seals are necessary and each of the seals are subjected to pressures equal to or higher than the high pumpcavity pressure during the injection stroke, the seals cause substantial resistance to piston movement and tend to tighten and increase frictional drag thereby causing an increased consumption of energy and result in the use of an amount of pumping energy substantially in excess of that which would be required to simply pump the liquid. Also since the injected liquid must be injected at a pressure higher than the pump discharge pressure, the area of the head of the double-headed piston which is exposed to the pump head cavity must be larger than the area of the head of the piston which pressurizes the injection fluid. Thus, the length of the stroke of the large area piston multiplied by its area produces a substantial negative volume which is lost from the positive displacement of the pumps piston cavity resulting in a capacity reduction of the pumping system by the amount. of the negative volume which decreases the efficiency of the pump. Also such high pressure injection devices require relatively elaborate construction and close dimensional and concentricity tolerances and are thus unavoidably expensive to manufacture.

Another injector arrangement takes the form merely of a supply line for the detergent admixture which is equipped with a unidirectional check valve, the supply line extending from a reservoir of the admixture to the pump head cavity. During the suction stroke of the pump, the negative pressure occurring in the pump cavity induces the flow of the injection fluid into the pump. Such arrangement is incapable of use where the pump is to be supplied by a pressurized source of water, such as in an industrial water line, since the prerequisite negative pressure may never occur in the pump head cavity. Moreover, at high admixture flow rates, the pressure head at the pumps inlet must be maintained at such low negative pressure as to frequently be detrimental to the pump.

Another type of prior injector device employs a replacement bolt-on pump head having a needle valve restriction to draw in and meter a quantity'of the detergent admixture into an injection fluid cavity when the pump is in its discharge stroke. The admixture is then forced from the chamber into the pump head cavity by a piston which is mechanically linked to the pump piston when the pump is in its discharge stroke. Such system is also inefficient since the needle valve restriction enhances cavitation of the admixture during each stroke when the adjusted quantity of admixture is less than maximum. Such cavitation starves the detergent cavity and reduces the total pump discharge by an amount equal to the degree of starvation. Moreover, the cylinder forming the injection fluid cavity must be precisely aligned with the pump piston to avoid mechanical binding forces which would cause the pump to malfunction.

The proportioning injector constructed in accordance with the principles of my invention obviates these disadvantages encountered in the prior pumps. Such injector is activated by dynamic fluid pulses emanating from the pumping piston of a positive displacement reciprocating pump eliminating the necessity of mechanical linkage between the pump and the injector to activate the injector. Moreover, the injector of my invention allows the introduction of a controlled and variable proportion of fluid, such as a detergent admixture, from an injection fluid source and will maximizing the overall satisfactorily whether the principal fluid inlet of the pump is supplied with a positive or negative pressure head, the injection fluid being introduced into the principal fluid under separate or different pressures either above or below atmospheric pressure. Also the injector of my invention provides a differential area injector piston member, the smaller area of which is exposed to the maximum pressure obtaining in the system, namely that of the cylinder head cavity, and thus only the smaller of the two piston head seals is ever exposed to maximum pressure. Such exposure results in the minimization of resistance of the sliding seals and the negative volume loss maximizing the overall pumping efficiency of the pump. Moreover, my injector includes a simple means for manually adjusting the proportion of the injection fluid'and the injector operates to inject the injection fluid during the intake cycle of the pump. Thus, the injection fluid is injected into the pump head cavity at a time when the pressure therein is minimized resulting in the loss of only a minimal amount of pump energy. Finally, the injector constructed in accordance with the principles of my invention is simple, accurate and is of a relatively low cost and may be constructed to be readily bolted on to preexisting positive displacement pumps in place of their conventional head plate or plates.

SUMMARY OF THE INVENTION In a principal aspect, the invention comprises a proportioning injector for fluids having a housing defining a passage extending therethrough and a chamber in the housing communicating with the passage intermediate the passage ends. Moveable volumetric varying means is located in the chamber and urging means is associated with the volumetric varying means to urge the varying means in first and second directions. When the varying means moves in the first direction the volume of the chamber is decreased passing a predetermined amount of the injection fluid into a fluid containing space when the space is at a first pressure. When a second pressure obtains in the space greater than the first pressure, the volumetric varying means moves in a second direction to increase the volume of the chamber. Nonretum means is provided to prevent the flow of fluid in the passage in but one direction.

These as well as other objects, features and advantages of the invention will become evident when considering the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING In the course of this description, the drawing will frequently be referred to, the drawing being a cross sectioned elevation view of a preferred embodiment of injector constructed in accordance with the principles of my invention and mounted on a double-acting positive displacement piston pump.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, a cutaway section of a conventional double-acting positive displacement piston pump housing 1 is shown having an inlet connection 2 which is adapted to be coupled to a source of principal fluid, such as water, and which communicates with an inlet passage 4 and an outlet connection 6 which communicates with a pump discharge passage 8. The pump also includes a double-ended pump piston 10 slideably disposed within a cylinder 12 and a pair of sleeves 13 and which is reciprocally powered intermediate its respective piston heads 16 and 18 by a power source (not shown). Each of the sleeves 13 carries an appropriate seal ring 20. lnlet 22 and 23 and discharge 24 and 25 unidirectional flow valves are mounted in the pump housing 1 and communicate between the inlet and discharge passages 4 and 8, respectively, and the pump head cavities 27 and 28. The inlet unidirectional valve 22 includes a generally cylindrical housing 30 which is stationarily mounted on an annular shoulder 31 formed in the pump housing 1. The housing 30 includes an annular upper flange 32 and an annular lower flange 33, the flange 33 forming a valve seat 34. A valve body 36 is moveably located in the housing 30 and is adapted to move in a direction parallel to the longitudinal axis of the housing. A compression spring 38 extends between the upper face of the valve body 36 and the flange 32 normally urging the valve body into sealing engagement with the valve seat 34. Although not shown in detail, the construction of the second inlet unidirectional valve 23 is substantially the same as that previously described, the valve 23 allowing flow of fluid only from the inlet passage 4 to the pump head cavity 28. The construction of the discharge unidirectional flow valves 24 and 25 is also substantially the same as that of the inlet valve 22, except that their valve bodies are reversed only allowing flow from the respective pump head cavities 27 and 28 to the discharge passage 8.

In the conventional pump housing which has been described, the pump head cavities 27 and 28 are generally formed by a concave head plate, such as the plate 40 shown in the drawing, which is bolted by bolts 42 to the pump housing 1 or fixed thereto by other suitable means. The preferred embodiment of injector of my invention may be mounted in place of one (as shown in the drawing) or both of such conventional head plates.

The injector comprises a housing, generally indicated as 44. Extending through the housing is a passage having portions 46 through 51, the various portions of the passage being bored in the housing 44. A generally cylindrical chamber 52 is provided in the housing 44 and extends in a direction generally perpendicular to passage portions 48 and 49.

A double-headed piston member 54 is provided in the chamber and is moveable along the longitudinal axes thereof. The piston member 54 includes a piston head 56 having a first area 58 exposed to the pump head cavity 27 and a second area 60 exposed to the chamber 52. A second piston head 62 is connected to the piston head 56 by a shaft portion 64, the second head having a larger area 66 than the areas 58 and 60 of piston head 58. Piston head 62 comprises an annular cupshaped cylinder 68 the open end of which extends toward the housing exterior.

A pair of compression springs 70 and 71 are disposed in the open cup-shaped end of piston head 62 and extend into a cupshaped adjusting plug 72 which is threaded into the distal end 74 of the chamber 52. The adjusting plug 72 includes an aperture 76 for venting the space between the adjusting plug and the piston head 62.

The chamber is of dual diameter, the distal end 74 having a larger diameter accommodating the enlarged piston head 62 and the end 78 of the chamber 52 adjacent the passage portions 48 and 49 has a smaller diameter portion. The transition between the larger and smaller diameter portions provides a step 80 which acts to limit the movement of the piston member 54 by engaging the piston surface 66 of the piston head 62. Movement of the piston member in the other direction is limited by the end surface 82 of the adjusting plug 72. Since the piston member 54 is moveable along the axes of the chamber 52, appropriate circular seals 84 and 86 are provided for preventing leakage of fluid past the sides of the piston heads. The piston heads 56 and 62 and the shaft portion 64 are preferably cast in one piece integral construction.

An inlet connection 88 is threaded into the passage portion 46 to adapt the passage to be connected with a source of injection fluid, such as a detergent admixture where the injector is to be employed in a cleaning process. The inlet connection 88 includes a longitudinal passage 90 which communicates with an enlarged diameter passage 92 having an annular flange 94 located at its distal end. A unidirectional nonreturn valve body 96 is located in the enlarged diameter passage 92 and is urged normally into a seating engagement with the stepped shoulder surface 98, formed at the transition between a small and larger diameter passages, by a compression spring 100.

A second nonreturn valve body 102 is located in a cavity 103 in a cup-shaped threaded plug 104 which is threadedly inserted in the passage portion 50. A compression spring 106 is carried in the cavity 103 and bears against the base of the valve body, normally urging the valve body 102 into seating engagement against a plate 108 having an aperture aligned with passage portion 49. A transverse passage 112 is bored through the plug 104, and communicates between the cavity 103 and the passage portion 51 which, in turn, communicates with the pump head cavity 27. An annular seal ring 114 is provided to prevent leakage of fluid past the threaded plug 104.

An adjustable needle valve 116 is also provided in the passage between the chamber 52 and the inlet connection 88. The needle valve is threaded into the housing at 118 and includes a conventional frustoconically tapered end portion 120 which extends into the cylindrical enlarged passage portion 47. The main body portion of the needle valve is axially located in a cylindrical portion 122 of the passage which has a diameter larger than the diameter of portion 47, the transition between the larger diameter portion 122 and the portion 47 providing an edge 124. Movement of the tapered portion 120 of the needle valve to the right or left, as viewed in the drawing, thus results in an increased or decreased spacing, respectively, between the frustoconical surface of the needle valve and the edge 124 forming an annular opening of variable cross-sectional area between same to adjust the flow of the detergent admixture fluid to the chamber 52.

In operation, let it be assumed that the pump piston 10 has just completed its intake cycle and pump piston head 16 is located in its maximum lowermost position (as viewed in the drawing) in the cylinder 12. The pump head cavity 27 is substantially filled with water which has been drawn into the cavity the unidirectional inlet valve 22 and the detergent admixture which has been passed to the cavity from the chamber 52. As the pump discharge cycle is commenced, the piston head 16 moves toward the housing 44, decreasing the volume of the pump cavity 27 by an amount equal to the volume which the pump piston head displaces. As the pressure in the pump head cavity 27 increases, the pressure exerts a force on the surface area 58 of piston head 56 of the piston member, urging the piston member 54 in an upward direction and overcoming the spring force exerted by the springs 70 and 71. Since the area 66 of the piston head 62 is greater than either areas 58 or 60 of piston head 56, upward movement of the piston member 54 operates to increase the volume of the chamber 52, in turn, reducing the pressure obtaining in the chamber. The degree of volume change in the chamber is a function of the length of travel of the piston member 54 and is thus controlled by the position of the end 82 of the adjusting plug 72, movement of the piston member 54 ceasing when the rim of the cup-shaped cylinder 68 of piston head 62 contacts the adjusting plug.

The decrease of pressure in the chamber 52 resulting from the increase in the volume, causes the nonreturn valve body 96 to move downwardly, as viewed in the drawing, and the detergent admixture which is to be eventually injected into the cavity 27 passes through the passage of the inlet connection 88, through the enlarged diameter passage 92 about the periphery of the valve body, through the adjustable annular opening defined by the edge 124 and frustoconical surface of the needle valve 116, through passage portions 47 and 48, and into the chamber 52, filling the increased volume chamber. Flow at this time through the passage 51 into the head cavity 27 is prevented by the seating of the nonreturn valve body 102 against the apertured plate 108 blocking the aperture therein. Seating of the nomaum valve body 102 is accomplished both by spring force of the spring 106 and by the increased pressure obtaining in the head cavity 27 which is transmitted to the valve body through passage 51, transverse passage 112 and cavity 103. During the discharge stroke of the pump piston the mixture present in the head cavity 27 is discharged through the discharge unidirectional valve 24 into the discharge passage 8 of the pump housing and out through the discharge outlet 6.

When the piston head 16 has reached its closest proximity to the housing 44, the piston head will commence movement in the opposite direction initiating the intake stroke. Upon the initiation of the intake stroke, the volume of the head cavity 27 is progressively increased by the piston head which is moving away from the housing 44, reducing the pressure obtaining in the head cavity 27. Upon such reduction in pressure, the pressure acting on the area 58 of the piston head 56 is substantially reduced to the point where it is not longer adequate to maintain the piston member 54 in its upward engagement against the adjusting plug 72 and the compression springs 70 and 71 again urge the piston member 54 in a downward direction, as viewed in the drawing. As the piston member 54 moves downwardly, the enlarged area 66 of piston head 62 reduces the volume of the chamber 52 increasing the pressure on the detergent admixture which had been previously drawn into the chamber during the discharge stroke of the pump. Such increase in pressure is transmitted back to the nonretum valve body 96 and acts on the valve body, along with the spring force exerted by the spring 100, to close the passage 90 and cut off the flow of detergent admixture through the inlet connection 88. The increase in pressure in chamber 52 is also transmitted through the passage portion 49 and aperture 110 in the apertured plate 108 to the valve body 102 and, together with the decreased pressure now obtaining in the pump cavity 27, overcomes the spring force exerted by spring 106, opening the valve body 102 and allowing flow of the admixture from the chamber 52, around the unseated valve body, and through the passage 51 into head cavity 27, mixing with the water which is entering the cavity through the inlet valve 22. Thus, injection is accomplished in the head cavity 27 at the decreased pressure which obtains during the intake cycle of the pump.

The volume of fluid injected may be readily adjusted by turning the threaded adjusting plug 72 in a direction either toward or away from the piston head 62, turning of the plug toward the piston head reducing the travel of the piston member 54 and thus reducing the volume of the fluid injected during any one cycle. Since the maximum pressure which obtains in any space at any one time is that obtaining in the pump cavity 27 during the discharge cycle, the smallest seal ring 84 only is subjected to such pressure since the smaller of the two piston heads of the piston member is the only piston head exposed to such maximum pressure. Thus, frictional resistance of the seals is substantially reduced as well as the detrimental excessive negative displacement of the piston head 56, substantially increasing the efficiency of the pump. Moreover, since the detergent admixture is injected when the pressure obtaining in the pump cavity 27 is at a minimum, substantial efiiciency is realized and injection is rendered possible even where the water is supplied to the inlet passage 4at a substantial positive pressure. Also since the piston member 54 is in no way mechanically connected to the pump piston 10, it may be located at any point in the pump cavity 27 obviating the necessity of close mechanical tolerances and clearances and resulting in a substantially simplified injector arrangement.

Although the preferred embodiment of injector has been shown as being installed as a replacement for only one head plate of a conventional double-acting piston positive displacement pump, it will be readily understood that the injector of my invention may be alternatively substituted for both head plates of such pump or may be employed with a single-acting positive displacement piston pump. Also the description of the arrangement in terms of a detergent injector should not be considered a limitation on the use of the injector. The injector of my invention is contemplated for use with fluids other than detergent admixtures and water. Moreover, it should be understood that the embodiment described is merely illustrative of one of the applications of the principles of the invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the inventron.

I claim: 1. A proportioning injector for fluids comprising, a housing having a passage extending therethrough, one end of said passage communicating with inlet means which is adapted to be connected with a source of a first fluid and the other end communicating with a space adapted to contain a second fluid, a chamber in said housing communicating with said passage intermediate its ends,

volumetric varying means moveably disposed in said chamber, said volumetric varying means having a first surface communicating with said space and a second surface communicating with said chamber, said second surface having an area greater than said first surface,

urging means including one of said surfaces associated with said moveable volumetric varying means urging said varying means in a first direction decreasing the volume of said chamber when said space is at a first pressure to pass a predetermined amount of the first fluid into the space and urging said moveable volumetric varying means in a second direction in said chamber increasing the volume of said chamber when said space is at a second pressure greater than said first pressure, and

nonretum means preventing the flow of the first fluid in but one direction in said passage.

2. The injector of claim 1 wherein said urging means comprises spring means acting upon one end of said volumetric varying means normally urging said varying means in said first direction and said first surface communicating with said space to overcome said spring means and urge said volumetric varying means in said second direction.

3. The injector of claim 1 wherein said volumetric varying means comprises,

a pair of piston heads,

a first of said heads having said first surface communicating with said space, and

the second of said heads having said second surface communicating with'said chamber.

4. The injector of claim 3 wherein said first head includes a third surface communicating with said chamber, said second surface having a greater area than said third surface.

5. The injector of claim 1 including means for variably adjusting said predetermined amount of said first fluid passed into said space from said chamber.

6. The injector of claim 5 wherein said adjusting means comprises a moveable stop member having thread means for adjustably engaging said stop member with said volumetric varying means.

7. The injector of claim 1 including adjustable flow varying means located between said inlet means and said chamber for varying the flow of the first fluid to said chamber.

8. The injector of claim 7 wherein said adjustable flow varying means comprises a needle valve.

9. The injector of claim 1 wherein said nonretum means comprises,

first moveable valve means in said passage between said inlet means and said chamber,

urging means urging said first valve means into a passage blocking position when said volumetric varying means is moved in said first direction and being overcome when said volumetric varying means is moved in said second direction to allow said first valve means to unblock said passage,

second moveable valve means in said passage between said chamber and said other end of said passage, and

urging means urging said second valve means into a passage blocking position when said volumetric varying means is moved in said second direction and being overcome when pump means is in its intake cycle and in said second direction to pass a predetermined amount of the first fluid from the inlet means to said chamber when the pump means is in its discharge cycle.

11. The injector of claim 10 wherein the positive displacement pump means is of the reciprocating piston type. 

1. A proportioning injector for fluids comprising, a housing having a passage extending therethrough, one end of said passage communicating with inlet means which is adapted to be connected with a source of a first fluid and the other end communicating with a space adapted to contain a second fluid, a chamber in said housing communicating with said passage intermediate its ends, volumetric varying means moveably disposed in said chamber, said volumetric varying means having a first surface communicating with said space and a second surface communicating with said chamber, said second surface having an area greater than said first surface, urging means including one of said surfaces associated with said moveable volumetric varying means urging said varying means in a first direction decreasing the volume of said chamber when said space is at a first pressure to pass a predetermined amount of the first fluid into the space and urging said moveable volumetric varying means in a second direction in said chamber increasing the volume of said chamber when said space is at a second pressure greater than said first pressure, and nonreturn means preventing the flow of the first fluid in but one direction in said passage.
 2. The injector of claim 1 wherein said urging means comprises spring means acting upon one end of said volumetric varying means normally uRging said varying means in said first direction and said first surface communicating with said space to overcome said spring means and urge said volumetric varying means in said second direction.
 3. The injector of claim 1 wherein said volumetric varying means comprises, a pair of piston heads, a first of said heads having said first surface communicating with said space, and the second of said heads having said second surface communicating with said chamber.
 4. The injector of claim 3 wherein said first head includes a third surface communicating with said chamber, said second surface having a greater area than said third surface.
 5. The injector of claim 1 including means for variably adjusting said predetermined amount of said first fluid passed into said space from said chamber.
 6. The injector of claim 5 wherein said adjusting means comprises a moveable stop member having thread means for adjustably engaging said stop member with said volumetric varying means.
 7. The injector of claim 1 including adjustable flow varying means located between said inlet means and said chamber for varying the flow of the first fluid to said chamber.
 8. The injector of claim 7 wherein said adjustable flow varying means comprises a needle valve.
 9. The injector of claim 1 wherein said nonreturn means comprises, first moveable valve means in said passage between said inlet means and said chamber, urging means urging said first valve means into a passage blocking position when said volumetric varying means is moved in said first direction and being overcome when said volumetric varying means is moved in said second direction to allow said first valve means to unblock said passage, second moveable valve means in said passage between said chamber and said other end of said passage, and urging means urging said second valve means into a passage blocking position when said volumetric varying means is moved in said second direction and being overcome when said volumetric varying means is moved in said first direction to allow said second valve means to unblock said passage.
 10. The injector of claim 1 including positive displacement pump means, said space comprising the pumping cavity of said pump means, said volumetric varying means moving in said first direction to pass a predetermined amount of the first fluid from said housing chamber to said pumping cavity when said pump means is in its intake cycle and in said second direction to pass a predetermined amount of the first fluid from the inlet means to said chamber when the pump means is in its discharge cycle.
 11. The injector of claim 10 wherein the positive displacement pump means is of the reciprocating piston type. 